Principles of Automotive Body Work

Undoing Dents

Collisions can cause severe damage to the body panels of any vehicle, often requiring a complete replacement. Where permissible, replacement body parts can be bought from junkyards to save money ordering new panels from the factory. Removing and replacing a damaged body panel can be both time consuming and frustrating. However, the experience is very rewarding when the job is done well.

Many times, auto body specialists can pound out dents when the rear of a panel is accessible. The goal is to restore the metal to its original shape. When a dent cannot be reached, metal pullers can be used to reverse a dent from the outside. Reusing existing metalwork speeds up the repair process, saves on cost, and often results in a better-looking repair.

Filling It In

Most of the time, metal still has crinkles and cracks in it after being hammered out, so auto body technicians must use Bondo or other fillers to restore a nice, smooth finish. Even some minor dents can be quickly repaired this way. The goal is to use as little filler as possible because over time, thick layers can crack and fall off. After spreading the filler on evenly, technicians must let it dry completely and then sand it down to blend with the surrounding surface.

Dealing with Rust

Rust is a serious auto body problem, especially in the North where winter roads expose cars to salt and sand. Auto body specialists can cut out rusted parts of vehicle bodies and weld new metal into its place. Welded spots must then be filed to surface level before using filler to blend the patched area with the rest of the body surface.


Sandpaper of 120- to 220-grit can be used to eliminate scratches and other auto finishing flaws. After getting below the paint, scratches can easily be filled before applying a new section of paint and clear coat.


Auto body specialists can use 400-grit sandpaper to prepare a car to receive a new coat of paint. They also use compounds to remove any oil on the surface so primer and paint will stick.

Written by